The backup software included with Maxtor's Shared Storage II doesn't require additional licenses. Unfortunately, while it can back up all clients to the shared disk, unique data on the shared disk can only be backed up to another, USB-attached storage device. Memeo, which came with the Buffalo device, doesn't support the iMac.

You could easily use the Backup utility that comes with Windows XP to set up bidirectional backups with any of these shared drives. However, I wanted the more advanced features in Retrospect, such as the ability to restore from a file version history, and I wanted to use one consistent utility that could back up both the iMac and Windows machines.

For my requirements, therefore, the Western Digital NetCenter gets the nod. One possible concern is the network speed - 100 Mb/sec. Ethernet versus 1,000Mb/sec. (1GB) for other units I tested. With my daughter getting into more streaming video and audio, I suppose that this could possibly make a difference -- if I had standardized the rest of my network on Gigabit Ethernet. I haven't, however, and I suspect that most home and small office users haven't either.

In fact, most home offices are using 802.11G wireless Ethernet, which runs at 54Mb/sec. at best. And with wired Gigabit Ethernet routers and adapters still selling for a premium, most users with wired Ethernet are still opting for 10/100 Ethernet devices, according to my local computer dealer. Finally, while multimedia files in my network are likely to be backed up to the network storage device, they will be played from the local disk drives on the OS X and Windows machines.

The 500GB NetCenter model I tested has more room than I need, and with a $399.99 list price ($275 street) it's at the high end of my budget.